Numerous variations of bicycles and tricycles are known in the prior art, and generally provide excellent exercise and transportation. However, these vehicles typically have used only the operator's legs to provide power. This exclusive reliance on leg power reduces the potential exercise benefits which could be obtained by utilizing both the arms and the legs to provide power. Similarly, utilizing the power of the arms to supplement that provided by the legs could allow greater speeds to be achieved and maintained. In addition, persons without the use of their legs, and who would not be able to use a conventional leg-powered cycle, could nonetheless operate a vehicle which utilized arm power.
Several cycles utilizing both arm and leg power are known in the prior art One example is shown in U.S. Pat. No. 1,020,432 to McBarnes, which discloses a bicycle powered by a linear reciprocating motion of the arms and legs. However, the McBarnes cycle requires simultaneous use of the arms and legs, which deprives the operator of the option of choosing an optimum combination of arm and leg usage. In addition, such a device would not be suitable for persons handicapped in the use of their legs. A similar problem would result with the Soviet Union Patent No. 800,011, which also requires simultaneous use of the arms and legs. Various attempts have been made to solve this problem, but the solutions have often required cumbersome and heavy equipment. In addition, the prior art configurations have also sometimes rendered operation of the vehicle awkward, and in particular have had less than optimum results with steering the vehicles. Examples of vehicles which permit the arms and legs to be used jointly or independently are shown in U.S. Pat. Nos. 3,760,905 to Dower and 4,508,358 to Erel. Further examples of background art may be seen in U.S. Pat. No. 4,541,647 to Braun and Soviet Union Patent No. 1,065,279.